The invention relates to a method for operating a tissue processor, and to the tissue processor. The tissue processor comprises at least one retort for receiving the tissue samples, and at least one container for stocking a process medium.
Biological tissue samples, in particular histological tissue samples, are often required in the fields of human and veterinary medicine, in particular as microscopic prepared specimens for the assessment of cells and their environment. For microscopic inspection, thin sections of the tissue sample must be prepared for assessment under the microscope, in incident or transmitted light, by an expert.
The production of thin sections, for example using a microtome, requires that the tissue sample have a certain strength so that thin, transparent sections having a thickness on the order of micrometers can be produced using a knife. For this purpose, the tissue sample must first pass through a treatment process in which it is fixed, dehydrated, cleared, and then infiltrated with a carrier material, preferably melted paraffin. These processes are often performed successively in a single unit called a “tissue processor”; this tissue processor contains for this purpose a closable process chamber called a “retort” that receives the various reagents, in particular process media, for carrying out the process steps at a suitable temperature and pressure.
One important process step in this context is infiltration of the tissue sample with the carrier material in order to stabilize and consolidate it. This infiltration process step is preceded by a clearing step in which alcohol residues still present from a preceding dehydration step are removed. The chemical solution used for this clearing step is xylene or a similar medium. In the subsequent infiltration step, in which the tissue sample is exposed to the carrier material (usually melted paraffin), xylene constituents that still remain are flushed out and taken up by the liquid carrier material, with the result that the carrier material in the retort becomes contaminated. Residual dehydration reagents are likewise removed during the clearing step. Constituents from the tissue sample itself can also contaminate the dehydration reagents, the clearing reagents, or the carrier material. It is therefore necessary to divide the individual process steps into multiple process substeps in which the tissue sample is exposed successively to a reagent of increasing purity.
If the infiltration process is divided into three process steps, for example, the tissue sample is then first treated, in a first process substep, with a first carrier material that can have a relatively high level of contamination (e.g. with xylene). This is followed, in a second process substep, by a second infiltration step using a second carrier material that has a higher degree of purity than the first carrier material. Lastly, the tissue sample is exposed, in a third process substep, to a third carrier material that has the highest degree of purity; the carrier materials can encompass the same or different reagents. In this fashion the tissue sample is completely infiltrated, in a process of substeps with carrier material of increasing purity, with carrier material that has sufficient quality to produce a good thin section in a microtome, and for a microscopic prepared specimen.
The use of multiple liquid process media having different degrees of purity requires that these process media be kept available in containers in a liquid state. If one of the process media is too highly contaminated, this usually affects the aforesaid first process medium, and it must therefore be replaced with a process medium having an improved degree of purity.
It is an object of the invention to describe a method for operating a tissue processor, and a tissue processor, that contribute in simple fashion to reliable operation of the tissue processor and/or to high quality in the completely processed tissue samples.
This object is achieved by a method for operating a tissue processor that is provided for the processing tissue samples and that comprises at least one retort for receiving the tissue samples and at least one container for receiving a process medium, said method comprising: transferring the process medium at least one of from the container into the retort and from the retort into the container; automatically measuring a measured value in the course of transferring the process medium, the measured value representing a characteristic property of the process medium; and identifying the process medium based on the measured value.
The tissue processor for performing the aforementioned method according to the invention comprises at least one retort for receiving the tissue samples; at least one container for receiving a process medium; a transfer mechanism for transferring the process medium at least one of from the container into the retort and from the retort into the container; an automatic measuring device for measuring a measured value in the course of transferring the process medium, the measured value representing a characteristic property of the process medium; and an identifier for identifying the process medium based on the measured value.
According to the invention, during the operation of a tissue processor a process medium is conveyed from a container into a retort, or from the retort into the container. The tissue processor is provided for the processing of tissue samples. The retort is provided for receiving the tissue samples. The container is provided for stocking the process medium. Upon conveyance of the process medium, a measured value that is representative of a characteristic property of the process medium is automatically acquired. Conclusions can therefore be drawn from the acquired measured value as to the characteristic property, and from the characteristic property as to the process medium currently being conveyed. The characteristic property is, for example, a density and/or a degree of purity of the process medium.
This makes it easy to detect whether the correct process medium for the next process step or process substep has been introduced into the retort, especially when multiple process media and/or process media having different degrees of purity are provided in corresponding containers, and thus contributes to reliable operation of the tissue processor. In other words, it is thereby possible to detect whether a container having one of the process media has been connected in error. It is further possible, without exchanging the erroneously connected container, to use the process medium stocked therein automatically for the correct process step or process substep.
Acquisition of the measured value, and detection, associated therewith, of the process medium being conveyed, furthermore makes it possible to detect, after a process step, whether the process medium is subsequently usable for the same process substep, or whether the process medium is so greatly contaminated that it can be used subsequently for a different process substep or must be replaced.